P795: NEUTROPENIA IN CHILDHOOD IS MOST FREQUENTLY DUE TO AN AUTOIMMUNE PROCESS AND HAS A BENIGN COURSE.
Authors: Konstantina Toutoudaki, Elena Solomou, Polyxeni Delaporta, Ioanna Bregova, Ilona Binenbaum, Marianna Tzanoudaki, Antonis Kattamis
Journal: HemaSphere (2023)

Topic: 12. Bone marrow failure syndromes incl. PNH - Clinical Background: Autoimmune neutropenia (AIN) is the most common form of chronic neutropenia, among children, especially of very young age. It is considered a benign condition, with spontaneous resolution, usually after 3-5 years. Aims: The purpose of our study was to record the characteristics and clinical course of children, investigated with suspected AIN. Methods: Patients evaluated in our clinic since 2010 for isolated neutropenia lasting more than 2 months were included in this report. Demographic, clinical, and laboratory data were recorded. Standard hematological parameters along with immunological profile and evaluation of anti-neutrophil antibodies were analyzed. Detection of anti-neutrophil antibodies was performed using different assays, including granulocyte immunofluorescence test (GIFT), granulocyte agglutination test (GAT), or/and monoclonal antibody immobilization of granulocyte specific antigens (MAIGA). The diagnosis of AIN was confirmed if at least one of the tests were positive. Results: Overall, 312 patients (172 female/140 male) were included in this series. The mean age at presentation was 16.95 (range: 0 - 176) months (mos). Neutropenia was an incidental finding in 57.9% of the cases, while in 32.2% neutropenia was detected during evaluation of an infectious process. Other reasons accounted for 9.9% of cases. On the day of anti-neutrophil antibodies testing, mean WBC was 6484/μL, with absolute neutrophil, lymphocyte and monocyte count being 622/μL, 4815/ μL, and 706/μL, respectively. Anti-neutrophil antibodies, suggestive of AIN, were detected in 231 (74%) patients. Of them, 65.4% had positive GIFT test, 45.5% had positive/ borderline GAT test, and 44.2% positive/borderline MAIGA. The mean lowest absolute neutrophil count (ANC) observed in patients with AIN was 316/μL, compared with 654/μL in patients with neutropenia who did not have detectable antibodies. Clinical follow-up was available for 161 patients with AIN; in 93 patients neutropenia resolved after a mean duration of 23,7 mos, while 68 subjects had persistent neutropenia at their last follow-up. The mean age at recovery from neutropenia was 39.3 mo. Concerning the clinical course, 19.8% of AIN patients had at least one hospitalization, related to neutropenia. The most common infections reported were soft tissue infections and/ or abscesses (15.1%,), respiratory tract infections (10.8%), gingivitis/stomatitis/periodontitis (10.6%) and otitis media (9%). 5% of patients required long term systematic treatment (antibiotic chemoprophylaxis, IVIG, or corticosteroids). No death or severe adverse events were observed. Summary/Conclusion: We report a large series of AIN patients from a single center and confirm that, despite profound neutropenia, the course of AIN is overall benign with spontaneous recovery. However, infections are common and hospitalization is required in some cases, especially at disease onset. Keywords: Anti-neutrophil antibody, Childhood, Autoimmunity, Neutropenia